# -*- coding:utf8 -*-
from __future__ import print_function
import datetime


def datetime_day_begin(date_time):
    """
    转变为当前时间的当天开始
    :param date_time: 
    :return: 
    """
    return datetime.datetime(date_time.year, date_time.month, date_time.day)


if __name__ == '__main__':
    print(datetime_day_begin(datetime.datetime.now()))